Procedure
Baseline. During baseline, the subjects recorded
the number and types of all caffeinecontaining
beverages they drank daily. The baseline
was 16 days for Subjects 1 and 2, and 14
days for Subject 3. At the end of baseline, they
met individually with the second author who
calculated their baseline daily intake of caffeine
in milligrams. The treatment goal for all
subjects was to decrease their daily caffeine intake
from their baseline level to 600 mg (fewer
than five cups of brewed coffee). This 600 mg
figure was subtracted from each baseline mean
and then divided by four (the number of treatment
phases) to yield the number of mg of
caffeine reduction for each phase. For example,
during baseline, Subject 2 consumed an average
of 1148 mg of caffeine daily. His caffeine reduction
for each phase was 137 mg (1148 mg
minus 600 mg divided by four).